using AxCopilot.Services.Agent;
using FluentAssertions;
using Xunit;

namespace AxCopilot.Tests.Services;

public class SessionLearningCollectorTests
{
    // ═══════════════════════════════════════════
    //  기본 동작
    // ═══════════════════════════════════════════

    [Fact]
    public void Empty_BuildInjectionMessage_ReturnsNull()
    {
        var collector = new SessionLearningCollector();
        collector.BuildInjectionMessage().Should().BeNull();
    }

    [Fact]
    public void Count_StartsAtZero()
    {
        var collector = new SessionLearningCollector();
        collector.Count.Should().Be(0);
    }

    [Fact]
    public void Clear_ResetsCount()
    {
        var collector = new SessionLearningCollector();
        collector.TryExtract("build_run", "error CS1234: Something failed\nMSBuild error", false);
        collector.Count.Should().BeGreaterThan(0);

        collector.Clear();
        collector.Count.Should().Be(0);
        collector.BuildInjectionMessage().Should().BeNull();
    }

    // ═══════════════════════════════════════════
    //  빌드/테스트 실패 추출
    // ═══════════════════════════════════════════

    [Fact]
    public void TryExtract_BuildRunFailure_ExtractsBuildConfig()
    {
        var collector = new SessionLearningCollector();
        var output = """
            Build FAILED.
            error CS0246: The type or namespace name 'Foo' could not be found
            TargetFramework: net8.0-windows10.0.17763
            MSBuild version 17.8.0
            """;

        collector.TryExtract("build_run", output, success: false);
        collector.Count.Should().Be(1);

        var msg = collector.BuildInjectionMessage();
        msg.Should().NotBeNull();
        msg.Should().Contain("[build_config]");
        msg.Should().Contain("CS0246");
    }

    [Fact]
    public void TryExtract_TestLoopFailure_ExtractsBuildConfig()
    {
        var collector = new SessionLearningCollector();
        collector.TryExtract("test_loop", "error TS2304: Cannot find name 'x'", success: false);
        collector.Count.Should().Be(1);
    }

    // ═══════════════════════════════════════════
    //  grep/glob 결과 추출
    // ═══════════════════════════════════════════

    [Fact]
    public void TryExtract_GrepSuccess_ExtractsCodeLocation()
    {
        var collector = new SessionLearningCollector();
        var output = """
            src/Services/Agent/IntentGateService.cs:10: something
            src/Services/Agent/SessionLearning.cs:5: another thing
            src/Services/Agent/SubAgentProfile.cs:20: more
            """;

        collector.TryExtract("grep", output, success: true);
        collector.Count.Should().Be(1);

        var msg = collector.BuildInjectionMessage()!;
        msg.Should().Contain("[code_location]");
        msg.Should().Contain("Services/Agent");
    }

    [Fact]
    public void TryExtract_GrepSingleFile_NoLearning()
    {
        var collector = new SessionLearningCollector();
        // 단일 파일 경로만 있으면 학습 가치 없음
        collector.TryExtract("grep", "src/file.cs:10: something", success: true);
        collector.Count.Should().Be(0);
    }

    // ═══════════════════════════════════════════
    //  프로젝트 메타 파일 추출
    // ═══════════════════════════════════════════

    [Fact]
    public void TryExtract_CsprojRead_ExtractsProjectStructure()
    {
        var collector = new SessionLearningCollector();
        var output = """
            <Project Sdk="Microsoft.NET.Sdk">
              <PropertyGroup>
                <TargetFramework>net8.0</TargetFramework>
              </PropertyGroup>
              <ItemGroup>
                <PackageReference Include="xunit" Version="2.9.0" />
                <PackageReference Include="FluentAssertions" Version="6.12.0" />
              </ItemGroup>
            </Project>
            """;

        collector.TryExtract("file_read", output, success: true);
        collector.Count.Should().Be(1);

        var msg = collector.BuildInjectionMessage()!;
        msg.Should().Contain("[project_structure]");
        msg.Should().Contain("net8.0");
        msg.Should().Contain("xunit");
    }

    // ═══════════════════════════════════════════
    //  런타임 감지 추출
    // ═══════════════════════════════════════════

    [Fact]
    public void TryExtract_DevEnvDetect_ExtractsDependency()
    {
        var collector = new SessionLearningCollector();
        var output = """
            .NET SDK version: 8.0.300
            runtime: Microsoft.NETCore.App 8.0.5
            node version: v20.10.0
            """;

        collector.TryExtract("dev_env_detect", output, success: true);
        collector.Count.Should().Be(1);

        var msg = collector.BuildInjectionMessage()!;
        msg.Should().Contain("[dependency]");
    }

    // ═══════════════════════════════════════════
    //  파일 조작 에러 추출
    // ═══════════════════════════════════════════

    [Fact]
    public void TryExtract_FileWriteFailure_ExtractsErrorPattern()
    {
        var collector = new SessionLearningCollector();
        collector.TryExtract("file_write", "Access denied: C:/readonly/file.cs", success: false);
        collector.Count.Should().Be(1);

        var msg = collector.BuildInjectionMessage()!;
        msg.Should().Contain("[error_pattern]");
        msg.Should().Contain("file_write");
    }

    // ═══════════════════════════════════════════
    //  FIFO 관리
    // ═══════════════════════════════════════════

    [Fact]
    public void TryExtract_FifoEviction_MaintainsMaxLimit()
    {
        var collector = new SessionLearningCollector(maxLearnings: 3);

        for (int i = 0; i < 5; i++)
        {
            collector.TryExtract("file_write", $"Error {i}: unique error message number {i}", success: false);
        }

        collector.Count.Should().BeLessOrEqualTo(3);
    }

    // ═══════════════════════════════════════════
    //  중복 방지
    // ═══════════════════════════════════════════

    [Fact]
    public void TryExtract_DuplicateContent_NotAdded()
    {
        var collector = new SessionLearningCollector();
        var output = "Access denied: C:/readonly/file.cs";

        collector.TryExtract("file_write", output, success: false);
        collector.TryExtract("file_write", output, success: false);

        collector.Count.Should().Be(1);
    }

    // ═══════════════════════════════════════════
    //  BuildInjectionMessage 포맷
    // ═══════════════════════════════════════════

    [Fact]
    public void BuildInjectionMessage_ContainsHeader()
    {
        var collector = new SessionLearningCollector();
        collector.TryExtract("file_write", "Error: something failed", success: false);

        var msg = collector.BuildInjectionMessage()!;
        msg.Should().StartWith("[System:SessionLearnings]");
        msg.Should().Contain("위 내용을 참고하여 동일 실수를 반복하지 마세요");
    }

    // ═══════════════════════════════════════════
    //  안전 가드
    // ═══════════════════════════════════════════

    [Theory]
    [InlineData(null, "output")]
    [InlineData("build_run", null)]
    [InlineData("", "output")]
    [InlineData("build_run", "")]
    [InlineData("  ", "output")]
    public void TryExtract_NullOrEmptyArgs_DoesNotThrow(string? toolName, string? output)
    {
        var collector = new SessionLearningCollector();
        collector.TryExtract(toolName!, output!, false);
        // No exception = pass
    }

    [Fact]
    public void TryExtract_LargeOutput_TruncatesWithoutCrash()
    {
        var collector = new SessionLearningCollector();
        // 50KB의 큰 출력
        var largeOutput = "error CS0001: Big error\n" + new string('x', 60_000);
        collector.TryExtract("build_run", largeOutput, success: false);
        // 크래시 없이 완료 = 성공
    }
}